Upper limb- ARM

What is the path of the median nerve in the arm?

Arises from the lateral and medial cords of the brachial plexus Runs along the anteromedial aspect of the arm with the BRACHIAL ARTERY (along the medial border of corachobrachialis and biceps) Halfway down the arm, crosses ANTERIOR to the brachial artery to lie medial to it at the cubital fossa (where it lies inferior to the bicipital aponeurosis) Doesn't give any branches in the arm

Path of the musculocutaneous nerve?

Arises from the lateral cord of the brachial plexus (C5-7) Pierces and supplies coracobrachialis (to enter the forearm laterally) Runs inferior to biceps, superior to brachialis --> lateral cutaneous nerve of the forearm just above the elbow

Path of the ulnar nerve in the arm?

Arises from the medial cord of the brachial plexus Runs with the brachial artery (medial to it) in the ANTERIOR compartment of the arm until halfway down -->pierces the medial intermuscular septum -->runs in a groove between the olecranon and medial epicondyle (posteriorly)

Formation and end of the brachial artery?

Axillary--> lower border of teres major--> BRACHIAL ARTERY--> splits into radial and ulnar at the level of the NECK OF THE RADIUS.

What structures lie in the cubital fossa?

Biceps tendon Brachial artery Median nerve (Lateral to medial) Also: radial nerve lateral to biceps tendon

What is the main flexor of the elbow?

Brachialis

What forms the floor of the cubital fossa?

Brachialis and supinator

What is the main flexor of the arm when it is abducted?

Deltoid (clavideltoid)

What is the shape of the medial head of triceps?

Expands below the spiral groove to cover the posterior surface of the humerus and both intermuscular septa.

Which muscles does the ulnar nerve supply?

FCU and the ulnar half of FDP.

From where does the long head of biceps brachii orginiate?

From WITHIN the capsule of the shoulder joint. Supraglenoid tubercle of the scapula.

What does the deep motor branch of the ulnar nerve supply?

Hypothenar eminence (abductor digiti minimi, flexor digiti minimi and opponens digiti minimi), all of the interossei (palmar and dorsal), ulnar 2 lumbricals (medial) and ends by supplying adductor pollicis.

How does the biceps tendon emerge from the shoulder joint capsule?

In a sleeve of synovial tissue, running in the BICIPITAL GROOVE of the humerus

Where does the bicipital aponeurosis insert?

It merges with the deep fascia of the forearm on the ulnar side to insert onto the subcutaneous border of the ulna.

What is the path of the cephalic vein?

Lateral aspect of the dorsal venous arch--> Crosses the anatomical snuffbox--> Ascends on the later aspect of the forearm and arm (winds around to become anterior around midway up the forearm) --> deltopectoral groove-->pierces clavipectoral fascia to join the AXILLARY VEIN

Triceps- heads: origins, insertions

Long head (medial): infraglenoid tubercle of the scapula. Lateral head: lateral lip of the spiral groove, above the deltoid tuberosity of the humerus Medial head: medial lip of the spiral groove. (Hence, radial artery and profunda brachii running along the spiral groove are BETWEEN the lateral and medial heads of triceps. - Insertion: a tendon via posterosuperior aspect of the olecranon NB the medial head also gives branches to be inserted into the capsule of the elbow joint

Function of triceps?

Long head stabilises glenohumeral joint Extension of arm and forearm

What is the path of the basilic vein?

Medial aspect of the dorsal venous arch--> Medial aspect of the wrist--> Medial aspect of cubital fossa--> Pierces deep fascia of arm halfway between shoulder joint and elbow to join venae comitantes (arround brachial artery) --> form AXILLARY VEIN

What does the superficial branch of the ulnar nerve supply?

Palmaris brevis and gives 2 digital branches to supply the skin of the ulnar 1 1/5 fingers.

Path of the medial cutaneous nerve of the forearm?

Pierces the deep fascia of the arm around midway (with the basilic vein, which pierces to join the venae comitantes) -->superficial -->supplies skin on inferior arm -->lies superficial to the bicipital aponeurosis (with the basilic vein) -->winds medially to supply skin on medial forearm

What is the path of the radial nerve in the arm and forearm?

Posterior cord of brachial plexus --> posterior compartment of arm, running along the spiral groove with profunda brachii (between the lateral and medial heads of triceps) -->pierces the lateral intermuscular septa in the arm to enter the anterior compartment ---> lies between brachioradialis and biceps at the cubital fossa -->BRANCHES: -SUPERFICIAL-->winds around the lateral forearm to supply lateral dorsum of hand and dorsum of 3 1/2 fingers. (The superficial branch runs underneath brachioradialis, LATERAL to the radial artery. Then it winds posteriorly around the radius at the wrist, under the brachioradialis tendon, to give DIGITAL branches as above. -DEEP (posterior interosseous nerve)-->traverses the oblique and transverse fibres of supinator-->supplies posterior forearm muscles MINUS brachioradialis and ECRL.

What is the sensory innervation of the radial nerve?

Posterior surface of the arm and forearm Anterolateral surface of the lower half of the arm Hand: posterior surface of the radial 3 1/2 fingers (including the dorsum of the hand until this point), not beyond the distal IP joints (median nerve supplies these).

Which 2 structures run in the spiral groove?

Profunda brachii and radial nerve. Proximal to the medial head of triceps. (Inferior to the lateral and long heads).

What is the function of the bicipital aponeurosis?

Protects the underlying nerves and vessels (brachial artery, median nerve) Also helps biceps to flex the elbow more efficiently because it provides another attachment (to the ulna)

Path of the brachial artery and median nerve in the arm

Run in a groove along the medial border of biceps--> cubital fossa.

Functions of biceps at the shoulder joint?

Stabilises the humeral head Weak flexion

Branches of the brachial artery?

Superior ulnar collateral (runs with the ulnar nerve- ie posteriorly between olecranon and medial epicondyle) Inferior ulnar collateral Nutrient branches to the humerus Branches to BBC Profunda brachii (runs in spiral groove with radial)

What lies superficial to the bicipital aponeurosis at the cubital fossa?

The basilic vein and medial cutaneous nerve of the forearm.

Through which structure does the ulnar nerve run at the wrist? What are its boundaries?

The canal of guyon. Between the pisiform and hamate. Superiorly: the palmar carpal ligament Inferiorly: the transverse carpal ligament

Which artery is the superficial branch of the radial nerve lateral to when it runs in deep to brachioradialis?

The radial artery

Path of the ulnar nerve in the forearm?

Ulnar nerve enters the anterior compartment of the arm at the elbow by passing between the heads of FCU -->runs with the ulnar artery in the forearm The palmar cutaneous branch arises mid-forearm to supply the SKIN ON THE MEDIAL SIDE OF THE PALM ONLY. The dorsal cutaneous branch winds around the ulna, deep to FCU to reach the dorsum. It supplies the skin on the medial half of the hand and the dorsum of the ulnar 1 1/2 fingers. Beyond the flexor retinaculum, the main ulnar nerve divides into the SUPERFICIAL and DEEP MOTOR branch. Superficial branch-->Palmaris brevis and gives 2 digital branches to supply the skin of the ulnar 1 1/2 fingers. Deep motor branch--> Hypothenar eminence (abductor digiti minimi, flexor digiti minimi and opponens digiti minimi), all of the interossei (palmar and dorsal), ulnar 2 lumbricals (medial) and ends by supplying adductor pollicis.

Deep venous drainage of the arm?

Veins accompany the MAJOR ARTERIES (=venae comitantes. Usually in pairs) Digital branches--> Superficial and deep venous arches--> Ulnar and radial branches respectively--> Brachial branches--> joined by basilic vein to form the axillary

When is biceps brachii a powerful supinator?

When the elbow is flexed